CN113015752B

CN113015752B - Ultraviolet assisted photo-initiated free radical polymerization

Info

Publication number: CN113015752B
Application number: CN201980074816.XA
Authority: CN
Inventors: C·多伦多夫; M·布勒歇尔; P·比尔甘斯
Original assignee: Solenis Technologies LP USA
Current assignee: Solenis Technologies LP USA
Priority date: 2018-10-01
Filing date: 2019-10-01
Publication date: 2023-10-24
Anticipated expiration: 2039-10-01
Also published as: US11041037B2; EP3861029B1; BR112021006350A2; EP3861029A4; JP7457009B2; US20200102414A1; EP3861029A1; JP2022501491A; WO2020072417A1; CN113015752A; KR20210068504A

Abstract

A process for preparing a polymeric product by inverse emulsion polymerization. The method includes adding an Ultraviolet (UV) photoinitiator to an inverse emulsion monomer formulation including a monomer, and irradiating the monomer formulation with an ultraviolet light source. The polymerization product is formed from the polymerization of monomers in the presence of an irradiated UV photoinitiator.

Description

Ultraviolet assisted photo-initiated free radical polymerization

Technical Field

The present disclosure relates to an improved polymerization process for the isothermal preparation of nonionic, anionic and cationic acrylamide-based inverse emulsion homopolymers and copolymers due to Ultraviolet (UV) -assisted photoinitiated free radical polymerization.

Background

In inverse emulsion polymerization, the hydrophilic monomers, typically in aqueous solution, are emulsified in a continuous oil phase using a water-in-oil emulsifier and polymerized using an oil-soluble or water-soluble initiator; the product is a viscous lattice comprising submicron, water-swellable hydrophilic polymer particle colloids suspended in a continuous oil phase. The technology is applicable to various hydrophilic monomers and oily media.

The polymerization of the inverse emulsion may be carried out in any manner known to those skilled in the art. Examples can be found in many references, including for example, allcock and campe, contemporary Polymer Chemistry (contemporary polymer chemistry), (Englewood Cliffs, n.j., priority-HALL, 1981), chapters 3-5.

Inverse emulsion polymerization is a standard chemical process for preparing high molecular weight water-soluble polymers or copolymers. In general, the inverse emulsion polymerization process is carried out by the following steps: 1) preparing an aqueous solution of the monomers, 2) contacting the aqueous solution with a hydrocarbon liquid containing a suitable emulsifying surfactant or surfactant mixture to form an inverse monomer emulsion, 3) subjecting the monomer emulsion to free radical polymerization, and optionally 4) adding a demulsifier surfactant to increase the conversion of the emulsion when added to water. Other forms of inverse emulsion polymerization use a solid emulsifier that has been melted prior to use and the emulsifier is added to the oil phase rather than the aqueous phase.

Inverse emulsion polymers are typically water-soluble polymers based on ionic or nonionic monomers. Polymers comprising two or more monomers, also referred to as copolymers, can be prepared by the same method. These comonomers may be anionic, cationic, zwitterionic, nonionic or combinations thereof.

Inverse emulsion polymerization is a type of free radical polymerization that typically begins with an aqueous phase that is blended with water, monomer, and surfactant, and then emulsions into a continuous oil phase. The most common type of inverse emulsion polymerization is a water-in-oil emulsion, in which water and monomer droplets are emulsified in a continuous phase of oil along with a surfactant. Water-soluble polymers, such as certain polyvinyl alcohols or hydroxyethyl cellulose, may also be used as emulsifiers/stabilizers. Inverse emulsion polymerization is used to prepare several commercially important polymers, the dispersion itself being the final product.

It is known to use a variety of initiator systems to prepare water-soluble and water-swellable polymers. Initiators are commonly used in chain-growth polymerization reactions, such as free radical polymerization reactions, to regulate the initiation reaction by heat or light. For example, it is common practice to use a redox initiator pair to polymerize water-soluble monomers, wherein free radicals are generated by mixing the monomers with a redox pair as a reducing agent and an oxidizing agent.

It is common practice to use an initiator, such as a thermal initiator, either alone or in combination with other initiator systems during the reaction, which includes any suitable initiator compound that releases free radicals at elevated temperatures. Other initiator systems based on other concepts include redox couple systems or photoinitiated initiator decomposition at specific wavelengths.

Thermal polymerization initiators are compounds that generate free radicals or cations upon exposure to heat. For example, azo compounds such as 2,2' -Azobisisobutyronitrile (AIBN) and organic peroxides such as Benzoyl Peroxide (BPO) are well known thermal radical initiators, and benzenesulfonate esters and alkyl sulfonium salts have been developed as thermal cationic initiators.

In the heat treatment, the residual monomer must be treated with a higher temperature or longer reaction time. In the heat treatment, the initiator decomposition is triggered at a specific temperature. Therefore, the emulsion must be heated to start the reaction. Thereafter, the emulsion is treated at a higher temperature to initiate more initiator decomposition and lower residual monomer. Another approach is to add a redox or other type of initiator at the end of the polymerization to reduce the amount of residual monomer.

In the heat treatment, after almost complete polymerization, standard thermal processes require additional time at higher temperatures to reduce residual monomer. From said higher temperature, the emulsion must be cooled via a distillation process. These steps are very time consuming.

Efforts have been made to accelerate the polymerization process and/or reduce unreacted monomers, but with limited effectiveness. Some of these efforts have been made by using various thermal initiators such as 2,2' -azobis [2- (2-imidazolin-2-yl) propane ] dihydrochloride, benzoyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, di-t-butyl peroxide, dicumyl peroxide and thermal cationic polymerization initiators such as benzyl (4-hydroxyphenyl) methyl sulfonium hexafluoroantimonate, dicyandiamide, cyclohexyl p-toluenesulfonate, diphenyl (methyl) sulfonium tetrafluoroborate, (4-hydroxyphenyl) methyl (2-methylbenzyl) sulfonium hexafluoroantimonate.

Photopolymerization initiators are roughly classified into three types according to the active species (radical, cation, anion) generated. Conventional photopolymerization initiators, such as benzoin derivatives, generate free radicals under irradiation with light. Photo-acid generators that generate cations (acids) under irradiation of light have been put to practical use in the late 1990 s. Light-base generators that generate anions (bases) under light irradiation are being studied for practical use.

Thus, process improvements have always been aimed at, for example, reducing the rapid batch preparation of residual monomers in the final product.

Disclosure of Invention

The present disclosure relates to a method of preparing a polymerization product by inverse emulsion polymerization. The method includes adding an Ultraviolet (UV) photoinitiator to an inverse emulsion monomer formulation comprising a monomer, irradiating the monomer formulation with an ultraviolet light source, wherein the polymerization is formed from polymerization of the monomer in the presence of the irradiated UV photoinitiator. When the polymer produced meets the individual product specifications, including, for example, molecular weight, properties, and low residual monomer content, then the process is complete and a polymerization product is formed.

Drawings

The present disclosure will be described hereinafter with reference to the following drawings.

FIG. 1-comparison of temperature profiles for laboratory batch preparation of standard temperature and UV-LED initiated cationic inverse emulsion polymers.

FIG. 2-comparison of temperature profiles for laboratory batch preparation of another standard temperature and UV-LED initiated cationic inverse emulsion polymer.

FIG. 3-comparison of temperature profiles for laboratory batch preparation of UV-LED initiated anionic inverse emulsion polymers.

FIG. 4-comparison of temperature profiles for laboratory batch preparation of UV-LED initiated anionic inverse emulsion polymers.

FIG. 5-comparison of temperature profiles for laboratory batch preparation of another standard temperature and UV-LED initiated anionic inverse emulsion polymer.

Detailed Description

The following detailed description is merely exemplary in nature and is not intended to limit the disclosure or the application and uses of the disclosure. Furthermore, there is no intention to be bound by any theory presented in the preceding background of the disclosure or the following detailed description.

The present disclosure relates to a method of improving an inverse emulsion polymerization reaction by adding an Ultraviolet (UV) photoinitiator to an inverse emulsion monomer formulation and irradiating the monomer formulation with an ultraviolet light source, thereby forming a polymerization product. .

During the whole reaction, under constant light irradiation, it is not necessary to bring the emulsion to a higher temperature to reduce the residues, and thus distillation from said higher temperature to room temperature is not necessary.

Surprisingly it was found that the use of UV initiator alone better controlled the reaction during the reverse phase polymerization reaction. Typically, thermal initiator decomposition occurs at a specific temperature and a specific rate. At higher temperatures, the rate of decomposition increases. The more initiator decomposes, meaning that the more starting polymer chains, the more exothermic polymer chain growth results. This results in more heat generation and more initiator decomposition than lower temperatures.

It has also been found that the preparation of homopolymers and copolymers of nonionic, anionic and cationic acrylamide groups can be improved by using Ultraviolet (UV) assisted free radical polymerization techniques, with reduced preparation times, without adversely affecting the properties, residual monomers or performance, compared to standard thermally induced inverse emulsion polymerization processes.

In the current process, the heat generated is controlled by distillation. It has been found that if only UV initiator is used in the inverse emulsion polymerization, the increase in temperature due to the propagation of the starting polymer chain does not lead to more initiator decomposition. Thus, the heat of reaction and the polymerization itself can also be controlled by the intensity of the UV light source.

It was also found that a higher light intensity at the end of the reaction leads to more initiator decomposition, which means less residual monomer and vice versa, i.e. with a small amount of initiator at the beginning, a higher intensity still means starting the polymerization. For example, turning off the ultraviolet light results in no decomposition of other initiators. Thus, UV light intensity and/or distillation may be used to control the polymerization reaction. This allows the polymerization reaction to be more controlled, thereby shortening the preparation time.

The inverse emulsion polymerization can be initiated at lower temperatures without the use of thermal initiators or without the need for thermal initiators, and the temperature during the reaction does not have to be kept at a well-defined temperature. This saves more time.

The monomer formulation may be any such formulation used in inverse emulsion polymerization. Nonionic monomers having reduced solubility in aqueous solutions can be used in the preparation of associative polymers. Examples include alkyl acrylamides; ethylenically unsaturated monomers having aromatic and alkyl side groups; ethers such as ethylene oxide, propylene oxide, and butylene oxide; and vinyl alkoxylates; an allyl group; alkoxylates and allylphenyl polyol ether sulfates. Exemplary materials include, but are not limited to, methyl methacrylate, styrene, t-octyl acrylamide, and allyl phenyl polyol ether sulfate, which is available from Clariant as Emulogen ^TM APG 2019.

Anionic monomers include free acids and salts thereof, such as acrylic acid; methacrylic acid; maleic acid; itaconic acid; acrylamidoglycolic acid; 2-acrylamido-2-methyl-1-propanesulfonic acid; 3-allyloxy-2-hydroxy-1-propanesulfonic acid; styrene sulfonic acid; vinyl sulfonic acid; vinyl phosphonic acid and 2-acrylamido-2-methylpropane phosphonic acid.

Cationic monomers include, for example, cationic ethylenically unsaturated monomers such as free bases or salts of diallyldialkylammonium halides, such as diallyldimethylammonium chloride; dimethylaminoalkyl (meth) acrylates, such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, 2-hydroxydimethylaminopropyl (meth) acrylate, aminoethyl (meth) acrylate, salts thereof and quaternary ammonium salts thereof; n, N-dialkylaminoalkyl (meth) acrylamides, such as N, N-dimethylaminoethyl acrylamide, and salts and quaternary ammonium salts thereof.

Nonionic monomers include, for example, acrylamide; methacrylamide; n-alkylacrylamides, such as N-methylacrylamide; n, N-dialkylacrylamides, such as N, N-dimethylacrylamide; methyl acrylate; methyl methacrylate; acrylonitrile; n-vinylmethylacetamide; n-vinylformamide; n-vinylmethylformamide; vinyl acetate; n-vinylpyrrolidone; hydroxyalkyl (meth) acrylates, such as hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate.

The comonomer may be present in any proportion. The resulting associative polymer may be nonionic, cationic, anionic, or amphoteric (comprising cationic and anionic charges).

In certain aspects of the present method, the uv-sensitive initiator is only sensitive to uv light. However, additional initiator may optionally be added to the inverse emulsion monomer formulation, such as a redox initiator, a thermal initiator, a photoinitiator, or a combination thereof.

In certain aspects of the present methods, the UV photoinitiator may be a compound having a functional group R-n=n-R ¹ Azo compounds of formula (I), wherein R and R ¹ May be aryl or alkyl, azobisisobutyronitrile, 2' -azobis [2- (2-imidazolin-2-yl) propane]Dihydrochloride (VA-044), 2' -azobis (2, 4-dimethylvaleronitrile) (V-65), benzoyl peroxide, 2-dimethoxy-2-phenylacetophenone (DMPA), 2,4, 6-trimethylbenzoyl phenyl phosphinate ]TPO-L) or any other photoinitiator and combinations thereof.

In other aspects of the method, the UV photoinitiator has an absorption bandwidth of about 280 nanometers (nm) to about 420nm, which may be about 320nm to about 400nm, which may be 365nm. In a preferred method, the ultraviolet photoinitiator exhibits absorption at 365nm. However, as polymerization proceeds, the initiator and light source are varied, it is envisioned that the process may be extended beyond these ranges.

UV-only initiators that are sensitive to UV-LED light emission at 365nm are typically water insoluble and relatively easy to find. Initiators with other absorption maxima are difficult to find and in most cases more expensive.

In certain aspects of the method, the UV light source may be a tube, a spray gun, or any other geometric shape. The light source may also be a fluorescent lamp, a mercury vapor lamp or any other type of UV light emitting source, such as an LED light source, or may be a combination thereof.

In addition, using LEDs as UV light sources can provide more energy to initiate the reaction, have a longer lifetime than many other light sources, require less implementation space, and can be tuned to other wavelengths to perform other polymerization processes when needed.

In certain aspects of the current methods, UV light may be applied to the emulsion. For example, a glass spray gun with a high intensity LED added at the tip of the spray gun may be placed directly into the emulsion, or the UV source may be placed outside the glass reactor, or a combination thereof may be used.

Regarding the intensity of the UV light source, several determinants are required to initiate and complete the polymerization reaction. For example, the light intensity will vary throughout the reaction because the opacity of the emulsion will vary and certain formulations and reactions are more turbid than others, thus requiring higher radiation intensities.

In certain aspects of the method, the UV light source may have an intensity of 0.15mW/cm ² Or higher, and may be 20mW/cm ² Or higher. In addition, the intensity of the light source may be varied at any time during the entire reaction.

It has surprisingly been found that it is the intensity of the UV light source that drives the reaction and not the amount of initiator. The intensity of the UV light source appears to be more important than the amount of initiator. For example, a lower initiator amount may be used to initiate the polymerization reaction. Conversely, when a lower intensity light source is used, a higher initiator amount is required and may result in a longer reaction time.

In certain aspects of the present methods, the initial temperature of the inverse emulsion reaction may be from about 0 ℃ to about 100 ℃, may be from about 20 ℃ to about 80 ℃, and may be from about 30 ℃ to about 50 ℃. Depending on the method used and the type of initiator, the polymerization is carried out until a discernible drop in distillate and/or temperature occurs.

The present process provides faster preparation time, less distillation and better reaction control. In addition, because the initiator is only sensitive to ultraviolet light, the initiator does not thermally decompose, as the reaction can be performed at a lower temperature, thus providing not only a faster reaction, but also a safer reaction.

The following examples are provided to illustrate certain aspects of the polymerization process.

Examples

When comparing standard thermally initiated inverse emulsion polymerization with current ultraviolet initiated inverse emulsion polymerization, the UV initiated step ensures time savings due to process improvements. These improvements are due to the fact that no additional reaction time is required at high temperatures to initiate more initiator decomposition, thus reducing the amount of residual monomer. Standard thermal polymerization processes use distillation to maintain temperature, thereby maintaining initiator decomposition and polymerization at a constant rate. Generally, after the reaction is almost completed, the polymer emulsion is brought to a higher temperature by stopping stirring and setting the ambient pressure. Initiator decomposition and polymerization can lead to an increase in the emulsion temperature, resulting in more initiator decomposition, which reduces residual monomer. At a specific temperature ("Tmax"), no further temperature increase was observed and distillation was used to reach a temperature at which batch preparation was completed.

When using thermally sensitive and/or UV sensitive only initiators, constant UV radiation during polymerization and distillation to reduce the temperature to a temperature of about 40 ℃ to complete the batch will ensure the same or less residual monomer while maintaining the same product specifications and properties.

Tables 1-5 and representative figures 1-5 show the time savings of thermally prepared polymers compared to the present UV process using only UV sensitive initiators. As can be seen from fig. 1 to 5, the time savings is 20 to 90 minutes depending on the particular polymer formulation and the particular "Tmax" temperature of the product.

It was also found that there was a higher intensity of the UV light source at the end of the reaction and distillation, and even though the amount of initiator was lower, the amount of residual monomer was in a lower range than in the standard thermal process.

The following UV initiated polymerization examples used a 4-diode source with DMPA as the sole initiator in molar amounts equal or lower than the thermal initiator used in the standard.

EXAMPLE 1 cationic acrylic-derived polyelectrolyte Using thermal initiator

An aqueous solution containing 267.7 grams of 43% acrylamide was used, 0.2 grams(10% solution, diethylenetriamine pentaacetic acid), 110.5 g of soft water, 430.8 g of 80% (2-acryloyloxy-ethyl) -trimethylammonium chloride (ADAME-Quat) solution and 0.14g of aqueous phase of 20% formic acid solution. The pH was adjusted to 3.02 with constant stirring using 2.3 g of 50% sulfuric acid solution.

By mixing 18 g of Lumisorb ^TM SMO (sorbitan monooleate surfactant), 13.1 g Genapol ^TM LA070S (ethoxylated fatty alcohol surfactant) and 8 grams of Rohamere ^TM 3059L (polymeric surfactant) was dissolved in 254.9 g Shellsol ^TM D80 (aliphatic mineral oil) and 0.025 g of 2,2' -azobis (2, 4-dimethylvaleronitrile) (V-65) was added with continuous stirring to prepare an oil phase.

The emulsion is prepared by dissolving the aqueous phase in the oil phase using a homogenizer to obtain a stable water-in-oil emulsion.

After transfer to a polymerization reactor comprising a thermometer, anchor stirrer, membrane and distillation bridge with attached vacuum pump, oxygen was removed via vacuum for 30 minutes.

The emulsion was heated to 56 ℃ with constant stirring and maintained at 53-56 ℃.

After collecting 95mL of distillate, stirring was stopped and the vacuum was set to ambient pressure under nitrogen.

After the temperature had reached equilibrium, the emulsion was cooled to a temperature of 40℃by distillation with continuous stirring, at which time 5 g of sodium peroxodisulfate solution (25% by weight in water) and 9.4 g of sodium metabisulfite solution (25% by weight in water) were added with continuous stirring, followed by 7.5 g of Genapol ^TM LA070S。

Table 1 and FIG. 1 show the standard temperature and UV-LED induced anionic inverse emulsion polymer Praeston ^TM K275 Comparison of temperature profiles for laboratory batch preparation of FLX. FIG. 1 shows each individual preparation step, showing the time saving for UV-LED initiated polymerization.

Example 2 cationic acrylic derived polyelectrolyte Using photoinitiator only

The product of example 2 was prepared as described in example 1, except that the thermal initiator was varied as follows.

A UV LED module with 365nm LEDs and 3.5W was placed beside the glass reactor at the same height as the emulsion. Other variations may place the UV spray gun below the emulsion surface inside the glass reactor, or the UV source inside the reactor, inside/above/behind the upper shell.

2.6 g of DMPA solution (2, 2-dimethoxy-2-phenylacetophenone, in Shellsol ^TM D80 of 1 wt%) was purged with nitrogen for 30 minutes and added to the deoxygenated water-in-oil emulsion with continuous stirring.

The uv intensity was adjusted to increase the emulsion temperature to about 53 ℃ to 57 ℃. The initial intensity of the outer wall of the glass reactor was from 2.85mW/cm ² Initially and during the reaction became 0.17mW/cm ² . The required intensity may be different from the intensity of this particular product due to the different uv geometry, power, location and initiator amount. The temperature was maintained at 53℃to 57℃and after 30mL of distillate was collected, an additional amount of 2.6 g of DMPA solution (in Shellsol ^TM 1 wt% in D80), wherein the intensity power of the UV-LEDs is increased to 1mW/cm ² To 2.85mW/cm ² 。

After an additional 60mL of distillate was collected, the UV-LED intensity was increased to 2.85mW/cm at two minute intervals ² 、9.7mW/cm ² And 16.1mW/cm ² At this time, the UV-LED intensity was 16.1mW/cm ² And 23mW/cm ² Between 2 and 5 minutes and the emulsion was cooled to 40 ℃ under constant uv irradiation. It should be noted that the amount of distillate may vary when other formulations, initiators, uv intensity, etc. are used.

Once the temperature reached 40 ℃, the ultraviolet irradiation was stopped and 5 g of sodium peroxodisulfate solution (25% by weight in water) and 9.4 g of sodium metabisulfite solution (25% by weight in water) were added with continuous stirring, followed by 7.5 g of Genapol ^TM LA070S (ethoxylated fatty alcohol surfactant).

Table 1 and FIG. 1 show the standard temperature and UV-LED initiated anionic inverse emulsion polymer Praeston ^TM K275 Comparison of temperature profiles for laboratory batch preparation of FLX (cationic inverse emulsion polymer) shows the time savings for UV-LED initiated polymerization

TABLE 1 Standard temperature and UV-LED initiated cationic inverse emulsion Polymer Praeston ^TM K275 Comparison of temperature profiles for laboratory batch preparation of FLX.

FIG. 2 shows a standard temperature and UV-LED initiated anionic inverse emulsion polymer Praeston ^TM K233 Comparison of temperature profiles of different laboratory batch preparations of (cationic inverse emulsion polymers) shows the time saving for UV-LED initiated polymerization.

Example 3-anionic acrylic-derived polyelectrolyte Using photoinitiator only

Example 3 was prepared as described in example 1, except that the thermal initiator, water and oil phase composition used, and the following differences were noted.

The aqueous phaseComprises 459.8 g of 43 wt.% acrylamide solution in water, 0.61 g(10 wt% solution, diethylenetriamine pentaacetic acid), 100 grams of soft water and 85.9 grams of acrylic acid. The pH was adjusted to 7.9 by adding 147.3 g of 32% by weight sodium hydroxide solution with constant stirring.

By stirring 25 g Zephrym under continuous stirring ^TM 7053 (Polymer surfactant) and 12 g Intrasol ^TM FA 1218/5 (ethoxylated fatty alcohol surfactant) was dissolved in 250 grams tetra-n-butane and 0.14 grams DMPA (2, 2-dimethoxy-2-phenylacetophenone) was added to make a fuel tank.

The uv intensity was adjusted to raise the temperature of the water-in-oil emulsion to 53 to 57 ℃ and the emulsion was maintained at that temperature until 75mL of distillate was collected. The UV-LED intensity was increased to 2.85mW/cm at two minute intervals ² 、9.7mW/cm ² And 16.1mW/cm ² At this time, the UV-LED intensity was 16.1mW/cm ² And 23mW/cm ² Kept for 2-5 minutes. The emulsion was cooled to 40 ℃ under constant uv irradiation.

After the temperature reached 40 ℃, the uv irradiation was stopped and 3.8 g of sodium peroxodisulfate solution (25% by weight in water) and 17 g of sodium metabisulfite solution (25% by weight in water) were added with continuous stirring, followed by 30g of Imbentin ^TM C125/060 (ethoxylated fatty alcohol surfactant).

Table 2, FIG. 3 shows the standard temperature and UV-LED initiated anionic inverse emulsion polymer Praeston ^TM A comparison of the temperature profile of a laboratory batch preparation of 3040L (anionic inverse emulsion polymer) shows the time saving for UV-LED initiated polymerization.

TABLE 2 Standard temperature and UV-LED initiated anionic inverse emulsion Polymer Praeston ^TM A3040L laboratory batch temperature profile comparison.

Table 3 and FIG. 4 show the standard temperature and UV-LED initiated anionic inverse emulsion polymer Praeston ^TM Comparison of laboratory batch prepared temperature profiles of 3030GB (anionic inverse emulsion polymer) shows the time saving of UV-LED initiated polymerization.

TABLE 3 Standard temperature and UV-LED initiated anionic inverse emulsion Polymer Praeston ^TM A 3030GB laboratory batch temperature profile comparison.

Example 4 anionic acrylic-derived polyelectrolyte Using thermal initiator

The emulsion of example 4 was prepared as described in example 1, except for the differences described below.

By mixing 300 g of Exxsol ^TM D100 ULA (aliphatic mineral oil), 18 g Span ^TM 80 and 20 g246 (polymeric surfactant) and adjusting the temperature of the oil phase to between 35 ℃ and 40 ℃.

Separately, an aqueous phase was prepared comprising 321 g of a 43 wt% aqueous acrylamide solution, 145 g of acrylic acid, 190 g of soft water and 1.5 g(10% by weight solution, diethylenetriamine pentaacetic acid). The pH was adjusted to 5.3 using 90.3 grams of 25 wt% aqueous ammonium hydroxide. The temperature after neutralization was 39 ℃.

The aqueous and oil phases were homogenized and mixed with a 4-blade glass stirrer bar while bubbling with nitrogen for 30-60 minutes. During nitrogen bubbling, the temperature of the emulsion was adjusted to about 40 ℃ to 45 ℃.

By adding 6.4 g lauroyl peroxide (in Exxsol ^TM D100 In ULA (aliphatic mineral oil)1.5 wt%, sparged with nitrogen for 30 minutes) and the temperature was raised to about 60 ℃ and held for 40 minutes, at which point stirring was stopped and the vacuum set to ambient pressure under nitrogen.

After the temperature had reached equilibrium, the emulsion was cooled to 40℃with continuous stirring, at which time 20 g of a 25% strength by weight aqueous ammonium hydroxide solution, 12 g of sodium metabisulfite solution (25% by weight in water), 15 g of Cirrasol were added with continuous stirring ^TM G1086 (nonionic polymeric surfactant), 5G Tetronic ^TM 1301 (ethoxylated fatty alcohol surfactant) and 5 grams of Synperonic ^TM AB 6 (ethoxylated fatty alcohol surfactant).

Table 4 and FIG. 5 show standard temperature and UV-LED initiated cationic inverse emulsion polymer Performance ^TM Comparison of the temperature profile of laboratory batch preparation of SP7200 (anionic inverse emulsion polymer) shows the time saving for UV-LED initiated polymerization, while table 5 shows the properties of the prepared product.

EXAMPLE 5 anionic acrylic-derived polyelectrolyte Using photoinitiator

Example 5 was prepared as described in example 4, except for the thermal initiator. Furthermore, UV-LED assisted photopolymerization as described in example 3 was used. In this example, after deoxygenation, 3.5 grams of DMPA solution (in Exxsol ^TM D100 To the emulsion was added 0.1 wt% in ULA (aliphatic mineral oil), sparged with nitrogen for 30 minutes, then after 25 minutes a second 3.5 g DMPA solution was added, then after 10 minutes a third 3.5 g DMPA solution was added. The UV-LED intensity was continuously adjusted to maintain the reaction temperature at 55 to 60 ℃.

It should be noted that the aforementioned UV polymerization may be accomplished at a distillation temperature of 45 ℃, 50 ℃, 55 ℃, 65 ℃, etc. The temperature profile is largely dependent on the UV intensity and the vacuum/distillation that brings heat/energy out of the system.

Tables 4 and 5 show polymer Performs prepared by inverse emulsion polymerization using a standard, thermally initiated inverse emulsion reaction ^TM Properties of SP7200 and products prepared using the present photoinitiation techniquesProperties of the material. The photoinitiated reaction was initiated at 365nm and 3.5W using a standard Osram UV lamp (Philips Cleo Performance W) and a UV-LED device with 4 diodes, showing the time savings for UV-LED initiated polymerization, while table 5 shows the properties of the prepared product.

TABLE 4 Performance ^TM Temperature profile of SP7200

Table 5: the prepared polymer Performance ^TM Properties of SP7200

*SP7200 specification

While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the disclosure in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiment or exemplary embodiments, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims and their legal equivalents.

Claims

1. A process for preparing a polymerization product by inverse emulsion polymerization, the process comprising:

adding an ultraviolet photoinitiator to an inverse emulsion monomer formulation comprising a monomer; and

irradiating the monomer formulation with an ultraviolet light source;

wherein only UV photoinitiators are used in the polymerization reaction;

wherein the polymerization reaction is controlled by UV light intensity and distillation, the initial temperature of the reaction is 50-80 ℃, constant UV radiation is used during the polymerization and distillation until the temperature is reduced to 40 ℃, followed by higher UV light source intensity at the end of the polymerization and distillation.

2. The method of claim 1, further comprising an additional initiator selected from the group consisting of a redox initiator, a thermal initiator, a photoinitiator, and combinations thereof.

3. The method of claim 1, wherein the ultraviolet photoinitiator is sensitive only to ultraviolet light.

4. The method of claim 1, wherein the ultraviolet photoinitiator is selected from the group consisting of a functional group R-N = N-R ¹ And wherein R and R ¹ Azo compounds which are aryl and/or alkyl, azobisisobutyronitrile, 2' -azobis [2- (2-imidazolin-2-yl) propane]Dihydrochloride, 2' -azobis (2, 4-dimethylvaleronitrile), benzoyl peroxide, 2-dimethoxy-2-phenylacetophenone (DMPA), 2,4, 6-trimethylbenzoyl phenyl phosphinate, and combinations thereof.

5. The method of claim 1, wherein the ultraviolet photoinitiator has an absorption bandwidth of 280nm to 420nm.

6. The method of claim 1, wherein the ultraviolet light has an intensity of 0.15mW/cm ² To 100mW/cm ² Within a range of (2).

7. The method of any one of claims 1 to 6, wherein the inverse emulsion polymerization is an ultraviolet initiated polymerization process.

8. A product prepared according to the method of any one of claims 1-6.